A data storage device including a flash memory and a controller. The flash memory includes a plurality of chips, each of the chips includes a plurality of pages, the pages are arranged to assemble into a super block, the pages of the super block are numbered 0˜X from top to bottom of the super block, the pages with number 0˜Y−1 constitute a data area, and the pages with numbers Y˜X constitute a RAID parity area. The controller corrects data of the data area according to data of the RAID parity area when the data in the data area cannot be successfully read.